diff options
Diffstat (limited to 'decoder.c')
| -rw-r--r-- | decoder.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/decoder.c b/decoder.c new file mode 100644 index 0000000..20799a3 --- /dev/null +++ b/decoder.c @@ -0,0 +1,234 @@ +/* Clzip - A data compressor based on the LZMA algorithm + Copyright (C) 2010 Antonio Diaz Diaz. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#define _FILE_OFFSET_BITS 64 + +#include <errno.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "clzip.h" +#include "decoder.h" + + +bool Ib_read_block( struct Input_buffer * const ibuf ) + { + if( ibuf->at_stream_end ) return false; + ibuf->stream_pos = readblock( ibuf->infd_, ibuf->buffer, Ib_buffer_size ); + if( ibuf->stream_pos != Ib_buffer_size && errno ) + { show_error( "read error", errno, false ); cleanup_and_fail( 1 ); } + ibuf->pos = 0; + ibuf->at_stream_end = ( ibuf->stream_pos < Ib_buffer_size ); + return !Ib_finished( ibuf ); + } + + +void LZd_flush_data( struct LZ_decoder * const decoder ) + { + const int size = decoder->pos - decoder->stream_pos; + if( size > 0 ) + { + CRC32_update_buf( &decoder->crc_, decoder->buffer + decoder->stream_pos, size ); + if( decoder->outfd_ >= 0 && + writeblock( decoder->outfd_, decoder->buffer + decoder->stream_pos, size ) != size ) + { show_error( "write error", errno, false ); cleanup_and_fail( 1 ); } + if( decoder->pos >= decoder->buffer_size ) + { decoder->partial_data_pos += decoder->pos; decoder->pos = 0; } + decoder->stream_pos = decoder->pos; + } + } + + +bool LZd_verify_trailer( struct LZ_decoder * const decoder, + struct Pretty_print * const pp ) + { + bool error = false; + File_trailer trailer; + const int trailer_size = Ft_size( decoder->format_version ); + for( int i = 0; i < trailer_size && !error; ++i ) + { + if( !Rd_finished( &decoder->range_decoder ) ) + trailer[i] = Rd_get_byte( &decoder->range_decoder ); + else + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "trailer truncated at trailer position %d;" + " some checks may fail.\n", i ); + } + } + } + if( decoder->format_version == 0 ) + Ft_set_member_size( trailer, LZd_member_position( decoder ) ); + if( !Rd_code_is_zero( &decoder->range_decoder ) ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "range_decoder final code is not zero.\n" ); + } + } + if( Ft_get_data_crc( trailer ) != LZd_crc( decoder ) ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "crc mismatch; trailer says %08X, data crc is %08X.\n", + (unsigned int)Ft_get_data_crc( trailer ), + (unsigned int)LZd_crc( decoder ) ); + } + } + if( Ft_get_data_size( trailer ) != LZd_data_position( decoder ) ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "data size mismatch; trailer says %lld, data size is %lld.\n", + Ft_get_data_size( trailer ), LZd_data_position( decoder ) ); + } + } + if( Ft_get_member_size( trailer ) != LZd_member_position( decoder ) ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "member size mismatch; trailer says %lld, member size is %lld.\n", + Ft_get_member_size( trailer ), LZd_member_position( decoder ) ); + } + } + if( !error && verbosity >= 3 ) + fprintf( stderr, "data crc %08X, data size %9lld, member size %8lld. ", + (unsigned int)Ft_get_data_crc( trailer ), + Ft_get_data_size( trailer ), Ft_get_member_size( trailer ) ); + return !error; + } + + + // Return value: 0 = OK, 1 = decoder error, 2 = unexpected EOF, + // 3 = trailer error, 4 = unknown marker found. +int LZd_decode_member( struct LZ_decoder * const decoder, + struct Pretty_print * const pp ) + { + unsigned int rep0 = 0; // rep[0-3] latest four distances + unsigned int rep1 = 0; // used for efficient coding of + unsigned int rep2 = 0; // repeated distances + unsigned int rep3 = 0; + State state = 0; + + while( true ) + { + if( Rd_finished( &decoder->range_decoder ) ) + { LZd_flush_data( decoder ); return 2; } + const int pos_state = LZd_data_position( decoder ) & pos_state_mask; + if( Rd_decode_bit( &decoder->range_decoder, &decoder->bm_match[state][pos_state] ) == 0 ) + { + const uint8_t prev_byte = LZd_get_byte( decoder, 0 ); + if( St_is_char( state ) ) + LZd_put_byte( decoder, Lid_decode( &decoder->literal_decoder, &decoder->range_decoder, prev_byte ) ); + else + LZd_put_byte( decoder, Lid_decode_matched( &decoder->literal_decoder, &decoder->range_decoder, prev_byte, + LZd_get_byte( decoder, rep0 ) ) ); + St_set_char( &state ); + } + else + { + int len; + if( Rd_decode_bit( &decoder->range_decoder, &decoder->bm_rep[state] ) == 1 ) + { + len = 0; + if( Rd_decode_bit( &decoder->range_decoder, &decoder->bm_rep0[state] ) == 0 ) + { + if( Rd_decode_bit( &decoder->range_decoder, &decoder->bm_len[state][pos_state] ) == 0 ) + { len = 1; St_set_short_rep( &state ); } + } + else + { + unsigned int distance; + if( Rd_decode_bit( &decoder->range_decoder, &decoder->bm_rep1[state] ) == 0 ) + distance = rep1; + else + { + if( Rd_decode_bit( &decoder->range_decoder, &decoder->bm_rep2[state] ) == 0 ) + distance = rep2; + else { distance = rep3; rep3 = rep2; } + rep2 = rep1; + } + rep1 = rep0; + rep0 = distance; + } + if( len == 0 ) + { + len = min_match_len + Led_decode( &decoder->rep_match_len_decoder, &decoder->range_decoder, pos_state ); + St_set_rep( &state ); + } + } + else + { + unsigned int rep0_saved = rep0; + len = min_match_len + Led_decode( &decoder->len_decoder, &decoder->range_decoder, pos_state ); + const int dis_slot = Rd_decode_tree( &decoder->range_decoder, decoder->bm_dis_slot[get_dis_state(len)], dis_slot_bits ); + if( dis_slot < start_dis_model ) rep0 = dis_slot; + else + { + const int direct_bits = ( dis_slot >> 1 ) - 1; + rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits; + if( dis_slot < end_dis_model ) + rep0 += Rd_decode_tree_reversed( &decoder->range_decoder, decoder->bm_dis + rep0 - dis_slot, direct_bits ); + else + { + rep0 += Rd_decode( &decoder->range_decoder, direct_bits - dis_align_bits ) << dis_align_bits; + rep0 += Rd_decode_tree_reversed( &decoder->range_decoder, decoder->bm_align, dis_align_bits ); + if( rep0 == 0xFFFFFFFF ) // Marker found + { + rep0 = rep0_saved; + Rd_normalize( &decoder->range_decoder ); + LZd_flush_data( decoder ); + if( len == min_match_len ) // End Of Stream marker + { + if( LZd_verify_trailer( decoder, pp ) ) return 0; else return 3; + } + if( len == min_match_len + 1 ) // Sync Flush marker + { + Rd_reload( &decoder->range_decoder ); continue; + } + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "unsupported marker code `%d'.\n", len ); + } + return 4; + } + if( rep0 >= (unsigned int)decoder->dictionary_size ) + { LZd_flush_data( decoder ); return 1; } + } + } + rep3 = rep2; rep2 = rep1; rep1 = rep0_saved; + St_set_match( &state ); + } + LZd_copy_block( decoder, rep0, len ); + } + } + } |